Rere1992

Hey everyone. So I've been dealing with an issue for awhile now and tried searching about for the answers.
My truck reeks of burning wire when the ac or heat is on. It also smells a very tiny bit when the system is set to off. I've changed the blower motor resistor already since the old one was rusted and burnt. I filled my ac system at the beginning of summer to see if it would hold refrigerant for any length if time. It lasted a week. When my defrosters are on, my condensor will turn on for a second, and then remain off for 5. And will continue the cycle. If I keep the heat on for a few min, the smell will eventually go away. (Unless I'm getting used to it lol.) My system also takes a few seconds to switch from defroster to another setting. (Like main straight vent.).
Now today, I was driving and the sun was coming through the windshield and I noticed a haze coming from the driver vent. The system wasn't on.
I've heard blower motor resistors will burn out when the blower motor ground is shot. I'll be checking it soon but was wondering if anyone had some Input on the issue.

Checked:
Blower motor resistor
Switch controls in dash

DFlintstone

Are you familiar with what anti freeze smells like? If you cool the windshield, maybe with a hose, do you see any condensation on the inside after running the defroster? Might be a heater core leak.

Rere1992

The heater core doesn't leak and the heat blows strong. I also don't see leak lines on the dust on the firewall. The heat does vaguely smell like anti freeze but my overflow/reservoir is cracked and leaks a little.

DFlintstone

Mine has a little pinhole. Doesent drip, doesn't affect how it works. It can smell, or fog the window if conditions are right. I add 1/2 a little tube of Alumaseal brand..that powdered aluminum, (no other brand!), after a coolant change, seems to mostly take care of it. Anyway watch for fogging when the windshield is cold.

Otherwise not much help here. Couple of things though. While I was chasing what I thought was a cowling leak, I cut open the right side of my cowl from above to get after it. Looking down through the duct from the cowl space to the lower, what do I see, Wires! I guess last century, some PO had the dash apart, and as they fit it back they got some of the wiring boogered up in the duct. The pinched wires are not shorting or grounding, in my case.

Last...I'm not sure if the XJ blower resistor involves wires that get hot. (My Jag does). If mice have been partying in there, they may have used those heating coils to make a little fire to keep warm....carpet fuzz might smell like burning insulation.

Rere1992

Now that I think about it, sometimes I'll get a little fog in middle/bottom of the windshield. The fan won't be on but it'll fog.